JP2000088747A - Meter for degree of ripeness - Google Patents

Abstract

PROBLEM TO BE SOLVED: To permit the highly accurate detection of the degree of ripeness without damaging fruits by using a plurality of LEDs as a light source, using a plurality of different wavelengths, and determining the degree of ripeness by the presence or absence of chlorophylls. SOLUTION: A sensor part formed of LEDs 1 and 2 covered with a hood F at the back surface of the main body of a meter for the degree of ripeness and a photodiode 3 is brought into contact with the surface of a fruit to be the object of ripeness degree measurement. By pressing a measurement switch D, the LEDs 1 and 2 continuously alternately irradiate red light (in the vicinity of 660 nm) and near infrared rays (in the vicinity of 880 nm), respectively, at the timing determined by a microcomputer 4, and the photodiode 3 receives part of the reflected light of the light diffused in the fruit. The infrared light of the LED 1 with the absorption wavelength of chlorophylls is diffused at the skin of the fruit, and its part is absorbed by chlorophylls. The majority of the infrared rays of the LED 2 is reflected. The photodiode 3 measures the amount of the infrared rays of the LED 1 absorbed by chlorophylls on the basis of the amount of the reflected light of the LED 2, and its relative value is taken as the degree of ripeness and displayed on a liquid crystal display.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for non-destructively measuring the ripeness of fruits and the like using light, and more particularly to an apparatus using an absorption wavelength specific to chlorophyll (chlorophyll). The present invention relates to a method for measuring the content of chlorophyll, fruit and the like, and judging the maturity.

[0002]

2. Description of the Related Art Heretofore, in order to determine the ripeness of fruits and the like, a hardness meter has been used, and the hardness has been determined based on the hardness at the time of breaking the epidermis of the fruits.

[0003]

Conventionally, in order to judge the ripeness of fruits and the like, a hardness meter for judging the ripeness from the hardness at the time of breaking the fruits has been used. It loses value and cannot be shipped. Moreover, the hardness tester is very expensive and the equipment is large.

[0004] Therefore, most farmers rely on visual observation and intuition from the appearance to determine the optimal harvest time and edible time of fruits, and there is a difference in actual ripeness.

[0005]

In order to achieve the above object, the maturity meter of the present invention measures the amount of chlorophyll contained in a fruit, not from the hardness of the epidermis of the fruit. Determine the degree. By using two wavelengths near 660 nm of red visible light, which is the absorption wavelength of chlorophyll, and near 880 nm of near infrared light which is not affected by it,
Unlike a conventional hardness tester, it is possible to determine a highly accurate ripeness without damaging the fruit.

Further, by using an LED as a light source, a small and inexpensive ripeness meter is provided. Since the LED has a relatively long life, trouble such as replacement can be omitted. The wavelength around 880 nm defined here is only adopted as a wavelength relatively unaffected by sugar, moisture, chlorophyll, etc.
It is not limited to this.

[0007]

1 and 2, a ripometer according to the present invention has a liquid crystal display E on a front panel A of the main body of the ripometer and a plurality of light emitting units on a rear panel B of the main body. L
An ED 1 and an LED 2, a plurality of photodiodes 3 serving as a light receiving unit, and a hood F made of a material such as rubber for covering the photodiodes 3 are provided for the purpose of blocking external light. , Measurement switch D. The external dimensions of the main unit are small enough to fit in the palm of your hand, and because it uses dry batteries as a power supply,
It is easy to carry.

LED 1 and LED covered with hood F
2 have different wavelength characteristics, and LED 1 has
Around 660 nm which is the absorption wavelength of chlorophyll, the other L
ED2 uses a wavelength around 880 nm which is relatively unaffected by the sugar content and water content of the fruit. LED1 and LED2
Are arranged in the hood F as light emitting units, and a plurality of photodiodes or phototransistors 3 are arranged as light receiving units in the center thereof. The LEDs 1 and 2 and the photodiode 3 are arranged in a circle, and can uniformly irradiate light when measuring a spherical fruit.

In FIG. 3, the surface of a fruit to be measured for ripeness is covered with a hood F at the back of the main body of the ripeness meter.
A plurality of LEDs 1, LED2 and photodiode 3
The sensor part consisting of is contacted to judge the maturity. The determination of the maturity is performed at a very high speed of about 0.1 to 0.2 seconds.

When the sensor is lightly brought into contact with the surface of the fruit and the measurement switch D is pressed, the LED 1 and the LED 2 emit red light and near infrared light intermittently and alternately at the timing determined by the microcomputer 4. The diode 3 receives the reflected light of a part of the light diffused inside the fruit. The red light of LED1, which is the absorption wavelength of chlorophyll, diffuses in the epidermis and inside of the fruit, and a part of it is absorbed by chlorophyll, and the infrared light of LED2 is hardly affected by chlorophyll and most of it is reflected. The photodiode 3 is
The reflected light returned from LED1 and LED2 is received, and L
Based on the amount of reflected light of ED2, how much red light of LED1 is absorbed by chlorophyll is measured. The relative value is displayed on the liquid crystal display E in two digits as the maturity. The microcomputer 4 averages the results of measurements performed a plurality of times (for example, 10 times) on the displayed ripeness, thereby improving the accuracy.

In FIG. 5, FIG. 5A and FIG.
Shows absorption wavelength curves of LED1 and LED2 in fruit. With reference to a wavelength around 880 nm,
5A and FIG. 5B, 6 in FIG.
The relative absorbance level around 60 nm is low and the reference 880
No difference from the wavelength near nm is observed. That is, it means that the chlorophyll in the fruit is small, and it is understood that the measured fruit is ripe. On the other hand, in FIG. 5-b, the difference in relative absorbance between the reference wavelength and the absorption wavelength of chlorophyll is remarkable. Therefore, it is understood that the chlorophyll is much and not ripe. Ripeness is determined from the difference between the relative absorbances of the two wavelengths.

FIG. 4 shows a block diagram of the ripness meter. Light emitted from the light emitting units LED1 and LED2 is diffused inside the fruit and reflected to the light receiving unit. LED1
In addition, the data of the light amount of the LED 2 first passes through both the DC and AC amplifiers, and is converted into an AC signal, and is not affected by extraneous light such as the sun. After that, the data enters the microcomputer 4,
The comparison operation is performed and the average data value is displayed on the liquid crystal display E.
Will be displayed.

[0013]

Since the present invention is configured as described above, the following effects can be obtained.

By measuring the ripeness using light, the fruit to be measured is not damaged.

The use of infrared light and red light as the light emitting portion of the ripeness meter increases the measurement accuracy of the ripeness measurement, and adopts an LED as a light source, thereby reducing costs compared to using a halogen lamp or the like. However, the size of the apparatus is also reduced. Since the power consumption is small, a dry battery can be used as a power supply, so that the portable battery can be carried and the fruit in a branch can be measured on the spot. Therefore, it is possible to measure the ripeness of the fruit of a specific tree following the growth process. By regularly measuring ripeness,
It is also possible to accurately determine the optimal time for harvesting and reduce damage during distribution. The microcomputer 4 averages the measured values ten times, so that highly accurate measurement results can be obtained. This measured value is displayed on the liquid crystal display E in two digits. As a result, the reliability of this measurement is greatly increased.

[Brief description of the drawings]

FIG. 1 is a diagram of measuring a ripeness by bringing a ripeness meter into contact with a fruit to be measured.

FIG. 2 is an external view of a ripeness meter

FIG. 3 is an exploded view of a ripeness meter.

FIG. 4 is a block diagram of a ripeness meter

FIG. 5 is an absorption wavelength graph of LED1 and LED2.

[Explanation of symbols]

 A front panel of ripeness meter main body B rear panel of ripeness meter main body C power switch D measurement switch E liquid crystal display F hood 1 LED 2 LED 3 photodiode 4 microcomputer

Claims (2)

[Claims] 1. A non-destructive ripeness meter characterized by using two or more different wavelengths and measuring the ripeness with or without chlorophyll. 2. The nondestructive maturity meter according to claim 1, wherein a plurality of LEDs are used as the light source.